Residential doors routinely cause severe injury when fingers are clamped between the door and the door jamb. As the door closes, the hinged edge of the door moves towards the door jamb, pinching fingers, sometimes with bone-crushing force. Door clamping injuries are painful and in severe cases, treatment requires finger amputation. Oftentimes, the victims are young children who do not understand the hazards of closing doors.
Clamping injuries can occur anywhere the door meets the door jamb. However, injury is most severe when it occurs on the hinged edge, where leverage from the door frame is greatest. This region, referred to as the “clamping region,” generates extreme compressive forces. It has been estimated that a door can produce clamping forces of up to 32,000 lbs. per square inch.
Finger blocking devices are known to be effective in preventing hinge-side clamping injury and are widely used in high risk environments such as daycare centers, nurseries, and homes with small children. However, success in the broader residential market has been limited due to aesthetic considerations. In particular, consumers find the appearance of blocking panels to be unacceptable. In residential applications, the appearance is so objectionable that blocking devices are often removed before the children have outgrown the risk.
Deformable materials have also been employed in certain areas of the door that cause injury. Deformable materials prevent injury by yielding to hands and fingers without crushing them. Yet, devices using deformable materials have never achieved market success due to the lack of a suitable hinge design. Currently, no hinge designs exist that are compatible with popular residential door styles, provide structural support across the deformable edge, and prevent clamping injury within the hinge leaves.